[PATCH v3 03/10] rootfs postprocess: clean python cache

[Felix Moessbauer <felix.moessbauer@siemens.com>]

When calling python scripts, python automatically creates cache files
to speedup future invocations of the same sources. This often happens
in postinst scripts, that directly run in the image chroot. The
created debian packages do not ship these files, as the debheper
scripts remove them before installing.

For the rootfs part, we manually have to do it to also not
include these in the final image. This patch implements this logic in
a custom cleanup postprocess step. As there might be situations where
shipping of a subset of the caches is desireable (e.g. readonly rootfs
images), we add support to control this logic using ROOTFS_FEATURES.

Signed-off-by: Felix Moessbauer <felix.moessbauer@siemens.com>
---
 meta/classes/image.bbclass  | 2 +-
 meta/classes/rootfs.bbclass | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/meta/classes/image.bbclass b/meta/classes/image.bbclass
index 9e0f5f7..6a3f99e 100644
--- a/meta/classes/image.bbclass
+++ b/meta/classes/image.bbclass
@@ -80,7 +80,7 @@ image_do_mounts() {
 }
 
 ROOTFSDIR = "${IMAGE_ROOTFS}"
-ROOTFS_FEATURES += "clean-package-cache generate-manifest export-dpkg-status clean-log-files clean-debconf-cache"
+ROOTFS_FEATURES += "clean-package-cache clean-pycache generate-manifest export-dpkg-status clean-log-files clean-debconf-cache"
 ROOTFS_PACKAGES += "${IMAGE_PREINSTALL} ${IMAGE_INSTALL}"
 ROOTFS_MANIFEST_DEPLOY_DIR ?= "${DEPLOY_DIR_IMAGE}"
 ROOTFS_DPKGSTATUS_DEPLOY_DIR ?= "${DEPLOY_DIR_IMAGE}"
diff --git a/meta/classes/rootfs.bbclass b/meta/classes/rootfs.bbclass
index 786682d..325e7ae 100644
--- a/meta/classes/rootfs.bbclass
+++ b/meta/classes/rootfs.bbclass
@@ -252,6 +252,12 @@ rootfs_postprocess_clean_debconf_cache() {
     sudo rm -rf "${ROOTFSDIR}/var/cache/debconf/"*
 }
 
+ROOTFS_POSTPROCESS_COMMAND += "${@bb.utils.contains('ROOTFS_FEATURES', 'clean-pycache', 'rootfs_postprocess_clean_pycache', '', d)}"
+rootfs_postprocess_clean_pycache() {
+    sudo find ${ROOTFSDIR}/usr -type f -name '*.pyc'       -delete -print
+    sudo find ${ROOTFSDIR}/usr -type d -name '__pycache__' -delete -print
+}
+
 ROOTFS_POSTPROCESS_COMMAND += "${@bb.utils.contains('ROOTFS_FEATURES', 'generate-manifest', 'rootfs_generate_manifest', '', d)}"
 rootfs_generate_manifest () {
     mkdir -p ${ROOTFS_MANIFEST_DEPLOY_DIR}
-- 
2.34.1